Refrigerated display case

ABSTRACT

A refrigerated display case includes an open front permitting customer access to the products contained therein and rear doors permitting access for restocking. An inner curtain of refrigerated air is circulated across the open front and adjacent surfaces forming a portion of the display case to refrigerate the contents therein. The case includes an air inlet extending along the lower front of the case for drawing cooled air therein which is then circulated rearwardly and discharged upwardly adjacent the exterior surface of the rear doors to prevent condensation thereon. The air stream adjacent the doors is then circulated over the top of the case and across the front of the case to form a guard curtain adjacent and outside the inner curtain of refrigerated air.

United States Patent [.191

Brown May 28, 1974 [54] REFRIGERATED DISPLAY CASE PrimaryExaminerWilliam J. Wye [75] hwcmor: Gram Brown. Atlanta Attorney, Agent,or FirmPrice, l'leneveld, Huizenga & Cooper [73] Assignee: KysorIndustrial Corporation,

Cadillac, Mich. [57] ABSTRACT 22 Filed; 7 1972 A refrigerated displaycase includes an open front permitting customer access to the productscontained [21] Appl- 312,977 therein and rear doors permitting accessfor restocking. An inner curtain of refrigerated air is circulated 52US. Cl 62/89, 62/256, 62/248, across the Open from and adjacent Surfacesforming a 9 /3 portion of the display case to refrigerate the contents[5 1] Int. Cl. F25d 17/06 therein The'case includes an air inletextending along [58] Field'of Search 62/248, 256,89, 25s; the lower fromof the case for drawing cooled air 9 /3 therein which is then circulatedrearwardly and discharged upwardly adjacent the exterior surface of the5 References Cited rear doors to prevent condensation thereon. The airUNITED STATES PATENTS stream adjacent the doors is then circulated overthe I top of the case and across the front of the case to form 327"62/256 a guard curtain adjacent and outside the inner curtain 3:675:4407/1972 Ibrahim 62/256 of 13 Claims, 5 Drawing Figures PATENTEDIAY 2 8 m4SHEEI 2 BF 3 lllllllllllllllllllllllllllllllllllll FIG. 2.

PATENTED MAY 28 m4 SHEEI 3 [IF 3 III I I l BACKGROUND OF THE INVENTIONThe present invention relates to a refrigerated display case of the typeemploying multiple air curtains extending across an open front.

In refrigerated display cases of the type which employ a curtain ofrefrigerated air extending across an open front, an air intake extendingalong the lower edge of the front of the case in alignment with the aircurtain is typically employed to collect the stream of refrigerated air.With such a system, a portion of the cold air forming the curtain tendsto mix with adjacent ambient air which is cooled thereby and falls overthe front of the case into the aisle. This mixing action which resultsin the loss of some of the refrigerated air not only reduces theefficiency of operation of the case, it also is frequently a cause ofdiscomfort to a consumer selecting products from the case. The removalof cooled air from the aisle in front of a refrigerated display casewith a blower has been suggested, but the cooled air so removed hasmerely been exhausted.

Open front refrigerated display cases frequently include glass accessdoors at the rear of the casefor allowing restocking and the like. Thecases typically are aligned along one end of a store thereby forming awall, with the rear doors of the case communicating with a room of theretail outlet behind the refrigerated display case. The glass doors canbecome fogged and/or frosted due to condensation, particularly when theroom behind the'case is not air conditioned and is relatively warm andhumid as during summer months. To reduce the condensation problem, somesystems have employed defrosters which force ambient or heated airadjacent the doors to evaporate the condensation. Although useful inproviding defrosting, the air so employed is not further utilized.

SUMMARY OF THE INVENTION The refrigerated display case of the presentinvention I solves the dual problem of cooled air spilled in an aislethis cooler air adjacent the exterior surface of the glass doors. Theair so circulated can be recirculated across the open front of therefrigerated display case to form a guard curtain. I

By employing the cool spilled air which is recircu lated around thecase, the efficiency of operation of the refrigeration system of thecase is-improved since the circulated spilled air is considerablycoolerthan the ambient air. It therefore forms a barrier to reduce heattransfer across the surfaces and open front of the case. Single paneglass access doors can be employed in place of the more expensivemultiple thickness type. In the event that the display case abuts an airconditioned room at the rear of the case, the recirculated air, which isrelatively cool, can eliminate condensation on the doors without loadingthe air conditioning system for the room behind the case as can occurwith conventional defrosting systems employing ambient or heated air,especially when several cases are used in an installation.

Refrigerated display cases embodying the present invention include anair inletextending along the lower front of the case for removing'coolair in an'aisle. Means are provided for forcing the cool air drawninwardly through the inlet adjacent the outside surface of an accessdoor at the rear of the case and for recirculating the air across theopen front of the case to form at least a portion of a guard curtain.

It is an object of the present invention to provide an improved methodfor removing cool air from an aisle in front of a refrigerated displaycase and for eliminating condensation on access doors at the rear of thecase.

An additionalobject of the present invention is to provide a method ofrecirculating air spilled over the front of an open front refrigerateddisplay case to form at least a portion of a guard curtain of air.

Another object of the present invention is to provide a refrigerateddisplay case with improved operating efficiency.

Still a further object of the present invention is to provide arefrigerated display case with a recirculated guard curtain of air atleast a portion of which is formed from recirculated cool air whichspilled over the front of the display case. I

An additional object of the presentinvention is to provide structure forrecirculating spilled air adjacent the outer surface of access doors atthe rear of a refrigerated display case to eliminate condensationthereon.

These and other objects of the present invention will become readilyapparent upon reading the'specification together with the accompanyingdrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a front perspective view ofa refrigerated display case embodying the present invention;

FIG. 2 is an enlarged fragmentary perspective view of a portion of therefrigerated display case shown in FIG.

FIG. 3 is a rear perspective view of the case shown in FIG. 1;

FIG. 4 is a cross-sectional view of the refrigerated display caseillustrating the flow of air therein taken along the section lines IV-IVof FIG. 3; and

FIG. .5 is a fragmentary cross-sectional view of a portion of the caseshown in FIG. 4 and taken along the section V-V in FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS.1-3, there is shown an open front refrigerated display case 10 havingend walls 12, a top cross member 14 and a bottom support member 15 whichextends between the end walls 12. The case so formed defines an openfronted compartment 16 with a rear wall 18 including three glass slidingdoors 20. Extending vertically between the sliding glass doors 20 arethe walls 19 of hollow return air ducts 36 (FIG. 5) which serve also assuperstructure supports for the case. Attached to walls 19 in anadjustable fashion, are a plurality of shelves 22 for holdingrefrigerated products 24 (FIG. 1). In addition to shelves 22, the bottomor bin 26 (FIG. 4) of the compartment is also capable of holdingrefrigerated products as seen in FIG. 1.

To maintain the low temperature of refrigerated products withincompartment 16, an inner curtain 30 of refrigerated air whose path isindicated by the dotted can comprise a honeycomb section of conventionaldesign for directing a refrigerated stream of air downwardly across theopen front of the case as seen in FIG. 4. Along the top edge offorwardly protruding lip 13 of the display case, i.e'., along theloweredge of the opening, there is provided an intake grill 34'extending thelength of the case for drawing the refrigerated curtain of air inwardlytherein. The airso captured is then recirculated adjacent the bottomshelf 26, the back-wall sections 19 and the top wall 25 as seen in FIG.4.

In addition to the refrigerated air curtain 30, the display caseincludes a second air curtain 40 indicated in FIG. 4 by the solid linearrows. Curtain 40 is adjacent to and exterior of the refrigeratedcurtain and is emitted from an outer nozzle 42 extending the length ofthe refrigerated display case-at the top of and exterior to nozzle 32asseen in FIGS. 2 and 4. Below thelip l3 and toward the upper portion of afront decorative panel 17 forming aportion of the display case 10,.thereis provided an air inlet 44 in which the cooled airspilled over lip 13is drawn to remove the air fromthe access aisle 2! in front of case 10.t j I The flow paths for thecurtains of air 30 and 40 together with thenovel structureand unique method of recirculating the outer curtain ofair to provide the dual function of removing cooled airfrom the accessaisle and eliminating condensation on the doors is explained in detailwith reference to FIGS. 3, 4 'and 5.

As seen in FIGS. 4 and 5, the inner'refrigerated curtain of air iscirculated through the intake grill 34 into a lower plenum chamber 35and thence into a plurality of ducts 36 extending upwardly adjacent thewalls v 19 of the rear wall ofthe'case. Ducts 36 communicate between thelower plenum 35 and an upper plenum 37 in whichthere is provided ablower 38 mounted on a baffle 38' andextending along the width of thecase.

Blower 38 forces the return air from ducts 36 into a refrigerationchamber 39 including evaporator coils 39 which refrigerate therecirculated air stream to sub-v zero temperatures. The recirculated airis then emitted through nozzle 32 downwardly across the open face ofcompartment 16 to complete one cycle of recirculatron.

Outer curtain 40 is emitted downwardly from nozzle 42 extendingacrossthe front of the vcase and travels downwardly adjacent and outside ofthe refrigerated curtain 30 across the open face of the case. During itsdownward travel, curtain 40 is cooled somewhat by the inner curtain andat the lip 13, mixed with whatever portion of the inner curtain thatisnot drawn inwardly through grill 34. Thus, the air curling over lip 13is a mixture of the inner and outer curtains 30 and 40 and ambient airand is considerably cooler than the ambient aisle air.

To draw the spilled air within inlet44 spaced above the floor, one ormore fans 46 are mounted in a baffle 47 extending between a rear plenum48 positioned below each sliding door structure 20. An intake duct LIIcommunicates between inlet 44 and fans 46. Fans 46 draw the spilled airinwardly through grill-34 and force the air outwardly through nozzles 49extending across 6 the top of plenums 48. Nozzles 49 are positionedalong the bottom edge of doors 20 adjacent the rear surfaces 4 23 of thedoors and extend approximately'the full width of the doors.

As seen in FIG. 4, the recirculated spilled air emitted by nozzles 49 isdirected against the rear surface 23 of the sliding doors 20 from eachof the nozzles 49 and travels upwardly and across the surface of thedoors. Air intakes 51 are provided at the top edge of doors 20 oppositenozzles 49. A duct 52 is coupled at one end to intakes 51 and at anopposite end to an intake plenum 53 on top of case 10(Plenum 53is shapedto accommodate a plurality of fans 56 mounted to a baffle 57 extendingacross the top of the display case. A solid panel 54 couples baffle 57to duct 52 such that the fans 56 force the cooled air gathered byintakes 51 through 5 nozzle 42 to form the guard curtain 40 therebycompleting the cycle of the recirculated cool air.

The recirculated cool air which travels adjacent rear surface 23 ofdoors 20 prevents the build-up of condensation on the doors which thencan be made from single panels of glass in place of the conventionallyemployed multiple panels; The efficiency of operation of the displaycase is greatly enhanced by recirculating the cool air adjacent theouter surface of the rear doors and other surfaces to aid in maintainingthe low temperature of the case while simultaneously removing the coolspilled air from the access aisle in front of the case. In addition,the-recirculated cool air formsthe guard curtain 40. a i

As will become readily apparent to those skilled in the art, variousmodifications to the present invention can be made. For example, therecirculation v.of the spilled air adjacent the outer surface of rearaccess doors can be used with refrigerated display cases employing agreater number of air curtains formed across the frontopening of thecase. it maybe desirable in some installations to replace the solidpanel 54 with an air input grill to permit ambient air at the top of thecase to be drawn inwardly and mixed with the cooled air to form theguard jet 40. The apparatus of the preferred embodiment, however,employs a solid panel. Additionally, the particularstructure employed todirect the recirculated spilled air across the face of the doors can bemodified. These and other-obvious modifications, however, will fallwithin the scope of the present invention as defined bythe appendedclaims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows. V

l. A method of reducing condensation on the exterior of an access door.at the rear of an open front refrigerated display case employing arefrigerated curtain of auto maintain the products refrigerated withinthe case comprising the steps of:

' collecting air spilled from said refrigerated curtain over the frontof said case; directing the collected air across the exterior surface ofthe access door from one edge thereof; collecting the air at a differentedge of the access door; and j recirculating the air collected duringthe last named collection step across the open front of saidrefrigerated display case. 7 2. The method as defined in claim 1 whereinsaid refrigerated display case employs an inner curtain of refrigeratedair and an outer guard curtain and said method includes the additionalsteps of:

mixing ambient air with air collected during the last named collectionstep; and

exhausting the mixed air across the front of the case to form the guardcurtain.

3. A refrigerated display case having a compartment with an open frontpermitting access to products therein, said case including:

at least one access door in a rear wall thereof;

means for forming a curtain of refrigerated air across the open front ofsaid case;

means for collecting cool air in an aisle adjacent the front of saidcase and for discharging the collected air across an exterior surface ofsaid access door from one edge thereof; and

means adjacent an opposite edge of said access door for receiving andmaintaining the stream of air across said door.

4. The refrigerated display case as defined in claim 3 and furtherincluding means for recirculating the received air across the open frontof said case.

5. The refrigerated display case as defined in claim 4 wherein saidmeans for forming a curtain of refrigerated air includesa nozzleextending across the open front of said case along the top thereof fordirecting refrigerated air downwardly; an intake grill extending acrossthe open front of said case near the bottom of the compartment forcollecting the refrigerated air curtain; and wherein said means forcollecting cool air includes an air inlet extending across saidrefrigerated display case below said intake grill.

6. The refrigerated display case as defined in claim 5 wherein saidmeans for discharging air across an exterior surface of said access doorincludes a nozzle extending adjacent said one edge of said access door.

7. The refrigerated display case as defined in claim 6 and furthercomprising air moving means communicating between said air inlet andsaid last named nozzle.

8. The refrigerated display case as defined in claim 7 wherein saidreceiving means comprises an air intake extending along'the edge of saidaccess door opposite said last named nozzle.

9. The refrigerated display case as defined in claim 4 wherein saidmeans for recirculating said received air comprises an outer nozzleextending across said refrigerated display case near the top thereof andair moving means communicating between said receiving means and saidouter nozzle.

10. The refrigerated display case as defined in claim 9 andfurtherincluding means for mixing ambient air with said received air to form aguard curtain of air exhausted across the front of said case exterior tosaid curtain of refrigerated air by said outer nozzle[ 11. Arefrigerated display case having a rear access door and an open frontpermitting customer access to the storage area therein, means forproviding a refrigerated air curtain extending across the open front toaid in maintaining the storage area refrigerated whereby therefrigerated air curtain tends to cause cool air to fall into the aisleadjacent said refrigerated display case, and means for circulating airfrom the aisle adjacent and below said storage area around saidrefrigerated display case in a path extending in part adjacent theexterior surface of the access door.

12. The 'refrigerated'display case as defined in claim 11 wherein saidcirculating means includes: 'an air inlet extending along saidrefrigerated display casebelow the storage area;

means for drawing air into said inlet from the aisle adjacent saidinlet; and

meanscoupled to said drawing means for directing air from the aisleacross the access door from one edge.

13. The refrigerated display case as defined in claim 12 wherein saidcirculating means further includes:

an air intake positioned adjacent an edge of the access door oppositesaid directing means; and meanscoupled to said intake for receiving airtherefrom and discharging the air across the open front of therefrigerated display case exterior to the refrigerated air curtain.

1. A method of reducing condensation on the exterior of an access doorat the rear of an open front refrigerated display case employing arefrigerated curtain of air to maintain the products refrigerated withinthe case comprising the steps of: collecting air spilled from saidrefrigerated curtain over the front of said case; directing thecollected air across the exterior surface of the access door from oneedge thereof; collecting the air at a different edge of the access door;and recirculating the air collected during the last named collectionstep across the open front of said refrigerated display case.
 2. Themethod as defined in claim 1 wherein said refrigerated display caseemploys an inner curtain of refrigerated air and an outer guard curtainand said method includes the additional steps of: mixing ambient airwith air collected during the last named collection step; and exhaustingthe mixed air across the front of the case to form the guard curtain. 3.A refrigerated display case having a compartment with an open frontpermitting access to products therein, said case including: at least oneaccess door in a rear wall thereof; means for forming a curtain ofrefrigerated air across the open front of said case; means forcollecting cool air in an aisle adjacent the front of said case and fordischarging the collected air across an exterior surface of said accessdoor from one edge thereof; and means adjacent an opposite edge of saidaccess door for receiving and maintaining the stream of air across saiddoor.
 4. The refrigerated display case as defined in claim 3 and furtherincluding means for recirculating the received air across the open frontof said case.
 5. The refrigerated display case as defined in claim 4wherein said means for forming a curtain of refrigerated air includes anozzle extending across the open front of said case along the topthereof for directing refrigerated air downwardly; an intake grillextending across the open front of said case near the bottom of thecompartment for collecting the refrigerated air curtain; and whereinsaid means for collecting cool air includes an air inlet extendingacross said refrigerated display case below said intake grill.
 6. Therefrigerated display case as defined in claim 5 wherein said means fordischarging air across an exterior surface of said accEss door includesa nozzle extending adjacent said one edge of said access door.
 7. Therefrigerated display case as defined in claim 6 and further comprisingair moving means communicating between said air inlet and said lastnamed nozzle.
 8. The refrigerated display case as defined in claim 7wherein said receiving means comprises an air intake extending along theedge of said access door opposite said last named nozzle.
 9. Therefrigerated display case as defined in claim 4 wherein said means forrecirculating said received air comprises an outer nozzle extendingacross said refrigerated display case near the top thereof and airmoving means communicating between said receiving means and said outernozzle.
 10. The refrigerated display case as defined in claim 9 andfurther including means for mixing ambient air with said received air toform a guard curtain of air exhausted across the front of said caseexterior to said curtain of refrigerated air by said outer nozzle.
 11. Arefrigerated display case having a rear access door and an open frontpermitting customer access to the storage area therein, means forproviding a refrigerated air curtain extending across the open front toaid in maintaining the storage area refrigerated whereby therefrigerated air curtain tends to cause cool air to fall into the aisleadjacent said refrigerated display case, and means for circulating airfrom the aisle adjacent and below said storage area around saidrefrigerated display case in a path extending in part adjacent theexterior surface of the access door.
 12. The refrigerated display caseas defined in claim 11 wherein said circulating means includes: an airinlet extending along said refrigerated display case below the storagearea; means for drawing air into said inlet from the aisle adjacent saidinlet; and means coupled to said drawing means for directing air fromthe aisle across the access door from one edge.
 13. The refrigerateddisplay case as defined in claim 12 wherein said circulating meansfurther includes: an air intake positioned adjacent an edge of theaccess door opposite said directing means; and means coupled to saidintake for receiving air therefrom and discharging the air across theopen front of the refrigerated display case exterior to the refrigeratedair curtain.